<template>
  <view>
    <!-- clilk只是方法名，可自定义 -->
    <my-search @click="gotoSearch"></my-search>
    <view class="scroll-view-container">
    <!-- 左侧 -->
    <scroll-view  class="left-scroll-view" scroll-y="true" :style="{height : wh + 'px'}" >
      <block v-for="(item,i) in cateList" :key="i">
        <view :class="['left-scroll-view-item',i === active ? 'active' : '']" @click="activeChanged(i)">
          {{item.cat_name}}
        </view>
      </block>
    </scroll-view>

    <!-- 右侧 -->
    <scroll-view class="right-scroll-view" scroll-y="true" :style="{height : wh + 'px'}"  :scroll-top="scrollTop">
    <view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
      <!-- 二级分类标题 -->
      <view class="cate-lv2-title">
      / {{item2.cat_name}} /
      </view>
      <!-- 三级分类 -->
     <view class="cate-lv3-list">
        <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodList(item3)">
          <!-- 接口中的web变成了dev，用replace替换可用 -->
          <image :src="item3.cat_icon.replace('dev','web')" mode="widthFix"/>
          <text>{{item3.cat_name}}</text>
        </view>
      </view>
    </view>
    </scroll-view>
    </view>
  </view>
</template>

<script>
  import badgeMix from '@/mixins/tabbar-badge.js'
  export default {
    data() {
      return {
        // 窗口的可用高度 = 屏幕高度 - navigationBar高度 - tarBar 高度
         wh:0,
         cateList:[],
         active: 0,
         cateLevel2:[],
         // 滚动条距离顶部的距离
         scrollTop:0
      };
    },
     mixins: [badgeMix],
    onLoad(){
      // 获取当前系统的信息
      const sysInfo = uni.getSystemInfoSync()
      // 为 wh 窗口可用高度动态赋值
      this.wh = sysInfo.windowHeight-50
      // 调用获取分类列表数据的方法
      this.getCateList()
    },
    methods:{
      async getCateList(){
      // 发起请求
      const { data : res } = await uni.$http.get('/api/public/v1/categories')
      // 判断是否获取失败
      if(res.meta.status !== 200) return uni.$showMsg()
      // 存储数据
      this.cateList = res.message
      // 为二级分类赋值
      this.cateLevel2 = res.message[0].children
      },
      activeChanged(i){
        this.active = i
        // 为二级列表重新赋值
        this.cateLevel2 = this.cateList[i].children
        // 让scrollTop的值在 0和1 之间切换
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      gotoGoodList(item3){
        uni.navigateTo({
          url:'/subpkg/goods_list/goods_list?cat_id='+ item3.cat_id 
        })
      },
      gotoSearch(){
       uni.navigateTo({
         url:'/subpkg/search/search'
       })
      }
    }
  }
</script>

<style lang="scss">
.scroll-view-container{
  display: flex;
  .left-scroll-view {
    width: 120px;
    .left-scroll-view-item {
      line-height: 60px;
      background-color: #f7f7f7;
      text-align: center;
      font-size: 12px;
      // 激活项的样式
      &.active{
        background-color: #ffffff;
        position: relative;    
        // 渲染激活项左侧的红色指示边线
        &::before {
          content: '';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #c00000;
          position: absolute;
          left: 0;
          top: 50%;
          transform: translateY(-50%);
        }
      }
    }
  }
  .cate-lv2-title{
        font-size: 12px;
        font-weight: bold;
        text-align: center;
        padding: 15px 0;
      }
  .cate-lv3-list{
    display: flex;
    flex-wrap: wrap;
    .cate-lv3-item{
      width: 33.33%;
      margin-bottom: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      image{
        width: 60px;
        height: 60px;
      }
      text{
        font-size: 12px;
      }
    }
  }
}
</style>
